Bao was given $\$1,\!000$ for his birthday. He decided to invest the money in a bank account that earns $10\%$ interest, compounded annually. In dollars, how much total interest will Bao have earned 3 years later?
Solution: Each year, the amount of money in the account is multiplied by 1.1.  Therefore, after 3 years the amount of money is $1000(1.1)^3=11^3=1331$ dollars.  The interest earned is $1331-1000=\boxed{331}$ dollars.